Smart kids like alcohol and marijuana, but avoid cigarettes - study

Brainy kids are more likely to take up drinking alcohol and smoking weed than their less gifted peers, new research has found.

But don't write them off as being not so clever after all - despite the drinking and toking, they stay well away from tobacco.

Researchers at University College in London looked at data covering more than 6000 UK adolescents. Their academic prowess was measured at 11, and substance use tracked until the end of their teens.

Brainy kids were more likely to drink alcohol in their early teens, and less likely to smoke tobacco. They didn't use marijuana much more than average kids, but in their late teens, were 50 percent more likely to indulge occasionally, and twice as likely to use on a regular basis.

And though they were more likely to drink, clever kids appear to understand their limits - they actually had lower rates of hazardous drinking (more than once a week on average) than their peers.

"Our finding that adolescents with high academic ability are less likely to smoke but more likely to drink alcohol regularly and use cannabis is broadly consistent with the evidence base on adults," author Dr James Williams writes in journal BMJ Open.

The study doesn't prove cause and effect either way, but the researchers propose it could be:

intelligent people are more likely to gravitate towards mind-altering substances

wealthier parents are more likely to consume, and better able to afford, alcohol and marijuana, and use them safely

they're also more likely to be non-smokers, and pass this trait onto their children

less-able children didn't realise 'cannabis' was the drug they were using, so answered the questions wrong

brainier kids are more likely to be accepted into older social groups with better access to restricted substances.